The synthesis of vitamin C from pectin as the starting material involves a reaction sequence long known to the art, being for example described in Research Paper RP 1594 entitled "Synthesis of Vitamin C from Pectin Substances" by H. S. Isbell (Journal of Research of the National Bureau of Standards, Vol. 33, July, 1944, pp. 45-61). In theory, this conversion sequence offers the advantage of commencing with rather inexpensive widely available agriculture by-products (e.g. beet pulp or citrus pulp). In commercial practice, however, vitamin C is synthesized from glucose.
The inventors herein have reinvestigated the conversion of pectin substances into Vitamin C and have concluded that one major step of the sequence, namely, conversion of L-galactonic acid into 2-keto-L-galactonic acid is difficult to carry out with high yield by chemical procedures, but might be carried out microbiologically. The microbiologic reaction offers considerable promise for reducing conversion cost substantially.